// Copyright 2023 TiKV Project Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package discovery

import (
	"github.com/tikv/pd/pkg/utils/etcdutil"
	"go.etcd.io/etcd/clientv3"
)

// Discover is used to get all the service instances of the specified service name.
func Discover(cli *clientv3.Client, clusterID, serviceName string) ([]string, error) {
	key := ServicePath(clusterID, serviceName)
	endKey := clientv3.GetPrefixRangeEnd(key)

	withRange := clientv3.WithRange(endKey)
	resp, err := etcdutil.EtcdKVGet(cli, key, withRange)
	if err != nil {
		return nil, err
	}
	values := make([]string, 0, len(resp.Kvs))
	for _, item := range resp.Kvs {
		values = append(values, string(item.Value))
	}
	return values, nil
}
